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(11) | EP 1 724 767 A8 |
(12) | CORRECTED EUROPEAN PATENT APPLICATION |
published in accordance with Art. 158(3) EPC |
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(54) | TRACKING ERROR SIGNAL GENERATION DEVICE AND TRACKING ERROR SIGNAL GENERATION METHOD |
(57) A detection signal S1 outputted from a light reception unit (11A) of detection means
(11) formed by four-division light reception element is added to a detection signal
S4 outputted from a light reception unit (11D) so as to obtain an addition signal
S14 and a phase difference signal P1 indicating the phase difference between the addition
signal S14 and the detection signal S1. Furthermore, a phase difference signal P4
indicating the phase difference between the addition signal S14 and the detection
signal S4 is obtained. The phase difference signal P4 is subtracted from the phase
difference signal P1 so as to generate a tracking error signal TE1.
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